EN 1993-1-1:2005+A1:2014 Clause 6.3.2.2 tells you to use \(M_{cr}\) with no clues on how to calculate it. \(M_{cr}\) is a purely theoretical value independent of any design code, so you can use any method you like to calculate it.

While any modern finite element package will calculate \(M_{cr}\), some codes offer hand methods:

- BS 5950-1:1990 Clause B.2.2 (more recent versions of BS 5950 donâ€™t give an explicit formula for \(M_{cr}\), but it can be deduced)
- BS 5400-3:2000 Clause 9.7.5 (rearrange in terms of \(M_{cr}\))
- PD 6695-2:2008+A1:2012 Clause 5.2 (equivalent to above BS5400 method)
- DD ENV 1993-1-1:1992 Clause F.1
- AS 5100.6-2017 Clause 5.6.1